Why don't researchers have standard ways to handle CGM data?
A major gap is the lack of standardized tools and methods for managing the flood of data CGM devices produce. In a 2025 study, researchers surveyed 43 CGM experts and interviewed 21 more — over 95% of them were not aware of any universally accepted guidelines for analyzing CGM data [3]. This means every research team essentially reinvents the wheel, making it hard to compare results across studies or trust that findings are robust.
The same study found that fewer than half of 89 recent clinical trials even described how they cleaned their CGM data or handled missing readings [3]. Without this transparency, it's impossible to know whether reported benefits are real or just artifacts of different data-handling choices. All 21 experts interviewed agreed that a shared repository of CGM data would improve research quality and speed innovation [3].
Is CGM only useful for diabetes? The research is lopsided.
The evidence for CGM is heavily skewed toward type 2 diabetes, leaving huge gaps for other populations and uses. A 2024 scoping review of 31 randomized controlled trials found that 65% focused on adults with type 2 diabetes, and 94% used HbA1c (a 3-month blood sugar average) as the main outcome [1]. This narrow focus means we have little rigorous evidence on how CGM might help with behavior change in people without diabetes, or in conditions like prediabetes or obesity.
Even within diabetes, the real-world results are mixed. A 2025 pilot study in a resource-limited inner-city hospital compared CGM to traditional finger-stick monitoring in 64 patients with very high blood sugar (HbA1c >9%). After adjusting for differences between groups, the CGM group actually had a 0.48% smaller drop in HbA1c — though this difference wasn't statistically significant [4]. The authors note that factors like insurance coverage, patient adoption, and provider training may explain why CGM doesn't always deliver in real-world settings [4].
Can CGM actually change behavior in non-diabetic groups?
There's very little evidence on whether CGM works as a behavior-change tool outside of diabetes. The 2024 scoping review found that only 42% of studies provided real-time CGM-based guidance on diet or activity, and most communication with participants happened just once per CGM wear session [1]. This suggests researchers haven't figured out how to best use CGM feedback to drive lasting changes in eating or exercise.
A 2021 pilot study in 50 adolescents with obesity tested time-limited eating (8-hour eating window) combined with CGM. While 90% of teens found the approach feasible and safe, there were no significant differences in weight loss, energy intake, or physical activity between groups [2]. The study was small and short (12 weeks), but it highlights that even when CGM is used, it doesn't automatically translate into better health outcomes — we need larger, longer trials to know what works.
About These Sources
This answer is built on 5 peer-reviewed studies — published from 2021 to 2025, 4 from 2024 or later, 4 in Q1 journals, collectively cited 80 times — selected as the most relevant from 5 studies that passed quality screening, drawn from 65 papers retrieved from a database of over 500 million.
Sources used in this answer
Leveraging continuous glucose monitoring as a catalyst for behaviour change: a scoping review
A 2024 scoping review of 31 RCTs found that 94% of CGM behavior-change studies focused on HbA1c in type 2 diabetes, revealing a research gap in broader applications for behavior change.
Time-Limited Eating and Continuous Glucose Monitoring in Adolescents with Obesity: A Pilot Study
A 2021 pilot study in 50 adolescents with obesity found time-limited eating plus CGM was feasible (90% adherence) but showed no significant weight loss or behavior changes compared to controls.
995-P: Current Gaps in CGM Data Tools and Methods
A 2025 survey and interview study found that over 95% of 21 CGM experts were unaware of standardized methods for analyzing CGM data, and fewer than half of 89 trials described how they handled missing data.
Evaluation of a Continuous Glucose Monitoring Based Regimen in a Resource-Limited Setting: A Pilot Study.
A 2025 retrospective study of 64 patients with uncontrolled type 2 diabetes found no significant HbA1c improvement with CGM versus finger-stick monitoring, suggesting real-world factors like insurance and training limit effectiveness.
Importance of FDA-Integrated Continuous Glucose Monitors to Ensure Accuracy of Continuous Glucose Monitoring
A 2024 review noted that non-FDA-approved CGM devices lack published accuracy studies, meaning their performance cannot be assumed equal to FDA-cleared integrated CGM systems.